U.S. patent number 6,986,934 [Application Number 10/909,684] was granted by the patent office on 2006-01-17 for thermoplastic planks and methods for making the same.
This patent grant is currently assigned to Mannington Mills, Inc.. Invention is credited to Hao A. Chen, Richard Judd.
United States Patent |
6,986,934 |
Chen , et al. |
January 17, 2006 |
Thermoplastic planks and methods for making the same
Abstract
A thermoplastic laminate plank is described wherein the
thermoplastic laminate plank comprises a core, a print layer, and
optionally an overlay. The core comprises at least one
thermoplastic material and has a top surface and bottom surface
wherein a print layer is affixed to the top surface of the core and
an overlay layer is affixed to the top surface of the print layer.
Optionally, an underlay layer can be located and affixed between
the bottom surface of the print layer and the top surface of the
core. In addition, a method of making the thermoplastic laminate
plank is further described which involves extruding at least one
thermoplastic material into the shape of the core and affixing a
laminate on the core, wherein the laminate comprises an overlay
affixed to the top surface of the print layer and optionally an
underlay layer affixed to the bottom surface of the print
layer.
Inventors: |
Chen; Hao A. (Chadds Ford,
PA), Judd; Richard (Newark, DE) |
Assignee: |
Mannington Mills, Inc. (Salem,
NJ)
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Family
ID: |
27039855 |
Appl.
No.: |
10/909,684 |
Filed: |
August 2, 2004 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20050003160 A1 |
Jan 6, 2005 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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09630121 |
Aug 1, 2000 |
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09460928 |
Dec 14, 1999 |
6617009 |
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Current U.S.
Class: |
428/195.1;
428/166; 428/149; 428/203; 428/44; 428/503; 52/586.1; 52/309.1;
428/46; 428/204; 428/201; 428/178; 428/148 |
Current CPC
Class: |
B29C
65/564 (20130101); B32B 27/06 (20130101); E04F
15/02033 (20130101); E04F 15/10 (20130101); B29C
48/11 (20190201); B29C 48/12 (20190201); E04F
15/02172 (20130101); B29C 66/72328 (20130101); B29C
66/72343 (20130101); B32B 27/10 (20130101); B32B
7/12 (20130101); B32B 29/005 (20130101); B32B
27/304 (20130101); B32B 3/06 (20130101); B29L
2024/006 (20130101); B32B 37/153 (20130101); B32B
38/145 (20130101); B32B 2471/00 (20130101); E04F
2201/0511 (20130101); E04F 2201/0523 (20130101); E04F
2201/0529 (20130101); B29K 2995/0089 (20130101); B29K
2995/007 (20130101); B29C 66/7315 (20130101); B29C
66/73151 (20130101); Y10T 428/31906 (20150401); Y10T
428/31866 (20150401); B29C 66/543 (20130101); Y10T
428/24802 (20150115); Y10T 428/162 (20150115); Y10T
428/16 (20150115); Y10T 428/24479 (20150115); Y10T
428/24421 (20150115); Y10T 428/24876 (20150115); Y10T
428/24777 (20150115); Y10T 428/24413 (20150115); Y10T
428/24661 (20150115); Y10T 428/2457 (20150115); Y10T
428/24868 (20150115); Y10T 403/559 (20150115); Y10T
428/31 (20150115); Y10T 428/18 (20150115); Y10T
428/24851 (20150115); Y10T 428/24562 (20150115); B29C
48/07 (20190201); B29C 48/17 (20190201); B29C
48/19 (20190201); B29C 48/20 (20190201); B29C
48/21 (20190201); B29C 66/71 (20130101); B29C
66/73161 (20130101); B29C 66/72329 (20130101); B32B
2327/06 (20130101); B32B 2260/028 (20130101); B32B
2317/125 (20130101); B32B 2260/046 (20130101); B29C
66/71 (20130101); B29K 2081/06 (20130101); B29C
66/71 (20130101); B29K 2079/08 (20130101); B29C
66/71 (20130101); B29K 2077/00 (20130101); B29C
66/71 (20130101); B29K 2071/12 (20130101); B29C
66/71 (20130101); B29K 2069/00 (20130101); B29C
66/71 (20130101); B29K 2067/06 (20130101); B29C
66/71 (20130101); B29K 2067/00 (20130101); B29C
66/71 (20130101); B29K 2055/02 (20130101); B29C
66/71 (20130101); B29K 2033/08 (20130101); B29C
66/71 (20130101); B29K 2031/04 (20130101); B29C
66/71 (20130101); B29K 2029/04 (20130101); B29C
66/71 (20130101); B29K 2027/06 (20130101); B29C
66/71 (20130101); B29K 2025/08 (20130101); B29C
66/71 (20130101); B29K 2025/06 (20130101); B29C
66/71 (20130101); B29K 2023/14 (20130101); B29C
66/71 (20130101); B29K 2023/12 (20130101); B29C
66/71 (20130101); B29K 2023/065 (20130101); B29C
66/71 (20130101); B29K 2023/0633 (20130101) |
Current International
Class: |
B32B
23/02 (20060101); E04F 15/10 (20060101) |
Field of
Search: |
;428/195.1,148,149,166,178,201,203,204,46,503,44
;52/586.1,309.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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3150352 |
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Oct 1982 |
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DE |
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3135716 |
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Jun 1983 |
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DE |
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33 43 601 |
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Dec 1983 |
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DE |
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42 42 530 |
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Dec 1992 |
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DE |
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2 557 905 |
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Jul 1985 |
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FR |
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1 430 423 |
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Mar 1976 |
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GB |
|
02095814 |
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Oct 1982 |
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GB |
|
02147856 |
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May 1985 |
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GB |
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3-169967 |
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Jul 1982 |
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JP |
|
57-119056 |
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Jul 1982 |
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JP |
|
405169534 |
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Jul 1993 |
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JP |
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WO 94/26999 |
|
Nov 1994 |
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WO |
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WO 95/11333 |
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Apr 1995 |
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WO |
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WO 96/07801 |
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Mar 1996 |
|
WO |
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WO 97/21011 |
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Jun 1997 |
|
WO |
|
Other References
Composite Panel Report: Laminate Flooring, "Wood Digest" Sep. 1999,
pp. 37. cited by other .
Copy of European Search Report dated Mar, 6, 2002. cited by
other.
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Primary Examiner: Watkins, III; William P.
Attorney, Agent or Firm: Kilyk & Bowersox, P.L.L.C.
Parent Case Text
This application is a continuation of U.S. patent application Ser.
No. 09/630,121 filed Aug. 1, 2000, which in turn is a
continuation-in-part of prior U.S. patent application Ser. No.
09/460,928 filed Dec. 14, 1999, now U.S. Pat. No. 6,617,009 B1 and
is incorporated in its entirety by reference herein.
Claims
What is claimed is:
1. A thermoplastic laminate plank comprising: a core comprising at
least one thermoplastic material and wood filler, wherein said core
has a top surface and a bottom surface, and opposing sides; a print
layer affixed to said top surface of said core, wherein said print
layer has a top surface and a bottom surface; and a protective
layer affixed to said top surface of said print layer, wherein said
thermoplastic laminate plank is domed and with the proviso that no
backing layer is located adjacent the bottom surface of said
core.
2. The plank of claim 1, wherein said wood filler is wood
flour.
3. The plank of claim 1, wherein said wood filler is present in an
amount of from 10 to about 35 parts by weight based on 100 parts by
weight of the thermoplastic material.
4. The plank of claim 3, wherein said wood filler is wood
flour.
5. The plank of claim 1, further comprising an underlay layer
located and affixed between said bottom surface of said print layer
and said top surface of said core.
6. The plank of claim 1, wherein said core further comprises at
least one plasticizer.
7. The plank of claim 6, wherein said at least one plasticizer is
present in an amount of less than about 20% by weight of said
core.
8. The plank of claim 1, wherein said at least one thermoplastic
material is polyvinyl chloride.
9. The plank of claim 1, wherein said core has a thickness of from
about 5 mm to about 20 mm, a width of from about 2 cm to about 30
cm, and a length of from about 30 cm to about 130 cm.
10. The plank of claim 1, wherein said core has a series of
paralleled cavities.
11. The plank of claim 1, wherein said plank has at least one
groove located on a side of said core.
12. The plank of claim 1, wherein said plank has at least one
tongue and one groove located on the plank.
13. The plank of claim 1, wherein two sides of said core are
tapered or have beveled edges, wherein said sides are opposite to
each other.
14. The plank of claim 1, wherein said print layer comprises an
aminoplast resin impregnated printed paper.
15. The plank of claim 14, further comprising a printed design.
16. The plank of claim 1, wherein said overlay comprises an
aminoplast resin impregnated overlay paper and aluminum oxide
imbedded on the top surface of said paper.
17. The thermoplastic laminate of claim 1, wherein said
thermoplastic material comprises at least one thermoplastic resin,
at least one processing aid, at least one impact modifier, at least
one lubricant, and at least one stabilizer.
18. The thermoplastic laminate of claim 17, wherein said
thermoplastic material further comprises at least one pigment.
19. A surface covering comprising a plurality of thermoplastic
laminate planks of claim 1, joined together.
20. The surface covering of claim 19, wherein said surface covering
is a floor covering that is a floating floor installation.
21. A floor covering comprising a plurality of thermoplastic
laminate planks, wherein said floor covering is a floating surface
and wherein said thermoplastic laminate plank comprises: a core
comprising at least one thermoplastic material and wood filler,
wherein each core has a top surface and a bottom surface, and
opposing side, and wherein said bottom surface is thermally treated
by direct heating of the bottom surface; a print layer affixed to
said top surface of said core, wherein said print layer has a top
surface and a bottom surface, and wherein said print layer includes
an aminoplast resin impregnated printed paper, and a protective
layer affixed to said top surface of said print layer, with the
proviso that no backing is located adjacent the bottom surface of
said core.
22. The floor covering of claim 21, wherein at least a portion of
said thermoplastic laminate planks are joined together by
splines.
23. The floor covering of claim 21, wherein at least a portion of
said thermoplastic laminate planks are joined together by a bonding
agent.
24. The floor covering of claim 23, wherein said bonding agent is
tetrahydrofuran, methylene chloride, a ketone, or combinations
thereof.
25. A thermoplastic laminate plank comprising: a core comprising at
least one thermoplastic material and wood filler, wherein said core
has a top surface and a bottom surface, and opposing sides; a print
layer affixed to said top surface of said core, wherein said print
layer has a top surface and a bottom surface, and wherein said
print layer includes an aminoplast resin impregnated printed paper;
and a protective layer affixed to said top surface of said print
layer, with the proviso that no backing layer is located adjacent
the bottom surface of said core, wherein at least said bottom
surface of the core is thermally treated by direct heating of the
bottom surface.
26. The plank of claim 1, wherein said core has a surface tension
of 34 dynes/cm or higher.
27. The plank of claim 1, wherein said core has a surface tension
of 45 dynes/cm or higher.
28. The plank of claim 1, wherein said core has moisture resistance
such that said core does not expand more than 0.04% in width or in
length when subjected to conditions that subject the core from
ambient conditions to 100% relative humidity and 90.degree. F.
29. A thermoplastic laminate plank comprising: a core comprising at
least one thermoplastic material and wood filler, wherein said core
has a top surface and a bottom surface, and opposing sides; a print
layer affixed to said top surface of said core, wherein said print
layer has a top surface and a bottom surface; a protective layer
affixed to said top surface of said print layer; a surface tension
of 34 dynes/cm or higher; and a moisture resistance such that said
core does not expand more than 0.04% in width or in length when
subjected to conditions that subject the core from ambient
conditions to 100% relative humidity and 90.degree. F.
Description
BACKGROUND OF THE INVENTION
Commercially available laminate flooring (using high or medium
density fiberboard or particle board as the core layer) has gained
overwhelming success in the flooring market. The growth rate of the
laminate flooring has remained in the double digits since the
product was introduced in the United States market. The success of
this product is credited to certain properties such as stain
resistance, wear resistance, fire resistance, good cleanability,
and the ability to use just about any type of printed design. In
addition, the overall emission of organic compound vapor is low and
the laminate flooring is considered color stable and
environmentally friendly over other competing flooring
products.
The biggest concern with commercially available laminate flooring
is the moisture resistance of the finished product and the
sensitivity of the raw materials (high or medium density
fiberboard, paper, and particle board) to moisture during the
manufacturing process. In some instances, the moisture can lead to
some serious quality control issues and application restraints. For
instance, and just to name a few, the higher moisture content in
the product, such as in the particle board or fiberboard, can cause
blistering and adhesion failure of the melamine surface to the
core. Also, higher moisture contents can lead to dimensional
instability of the finished product, which then results in the
cupping or doming of the product, which is extremely undesirable,
especially when installers are laying down the flooring. Also,
excessive moisture contents can create edge peaking due to the
swelling of the product and such edge peaking can result in edge
chip-off or premature wear-out or can soil more quickly. The
susceptibility to moisture content also leads to some installers
not wishing to place such laminate flooring in areas which are
subject to having water on the surface of the floor, such as in the
kitchen and bathroom areas.
The suppliers of such laminate flooring have appreciated the
problems associated with their products and have attempted to
overcome these problems by developing laminate flooring having
better moisture resistance by using melamine, phenolic, or
isocyanate binders to partially replace urea resins present in the
laminate flooring. While this improvement has made the product more
moisture resistant, the current commercially available laminate
floorings are still prone to moisture damage. For instance, the
thickness swelling of laminate flooring can increase by 10% and
water absorbency can exceed more than 15% according to the 24 hours
water absorption test. Another attempted solution at the moisture
resistance weaknesses of current laminate flooring has led some
manufactures to apply a water-repellant material on the upper edges
of the tongue and groove areas which further serve to resist any
moisture penetration through joints. Still another attempted
solution involves applying silicone caulk to seal the edges and
voids of the laminate perimeter where the laminate flooring meets
the wall. However, if very stringent installation instructions are
not followed, the laminate flooring will still be subjected to
moisture damage.
Accordingly, there is a need to develop a laminate flooring system
which overcomes the above weaknesses and disadvantages of current
commercially available laminate flooring.
SUMMARY OF THE INVENTION
A feature of the present invention is to provide a laminate plank
which can be used in a surface covering system which provides
improved moisture resistance and is not susceptible to damage
caused by moisture.
Another feature of the present invention is to provide a laminate
plank and surface covering system which is economically feasible
and permits easy installation and flexibility.
A further feature of the present invention is to provide a flooring
system that improves foot comfort and other ergonomic benefits.
An additional feature of the present invention is to provide a
surface covering system having improved sound deadening and other
reduced sound transmission benefits.
Still another feature of the present invention is to provide a
surface covering system which has significant improvements with
respect to ease of installation and includes a fool-proof
installation design and technique.
Another feature of the present invention is to provide a surface
covering system which avoids the use of a wet adhesive application
method.
Another feature of the present invention is to provide a flooring
system that has great flexibility so as to make various shapes,
sizes, and bevel edges.
Another feature of the present invention is to provide a flooring
system that can alleviate the requirement of installing the plank
in a given orientation.
Also, a feature of the present invention is provide a surface
covering system which has the ability to tolerate some
imperfections in the sub-floor or substrate and thus avoid
telegraphing the imperfections on the surface covering itself.
A further feature of the present invention is to provide a surface
covering system which has improved damaged resistance properties,
such as improved impact strength and the like.
Additional features and advantages of the present invention will be
set forth in the description which follows, and in part will be
apparent from the description, or may be learned by practice of the
present invention. The features and other advantages of the present
invention will be realized and attained by means of the elements
and combinations particularly pointed out in the written
description and appended claims.
To achieve these and other advantages and in accordance with the
purpose of the present invention, as embodied and broadly described
herein, the present invention relates to a thermoplastic laminate
plank, wherein the laminate plank has a core comprising at least
one thermoplastic material, wherein the core has a top surface and
a bottom surface. Optionally affixed to the top surface of the core
can be a print layer, wherein the print layer has a top surface and
a bottom surface. Also, an overlay layer can be affixed directly to
the top surface of the core, or, if a print layer is provided,
affixed to the top surface of the print layer. The plank can
optionally contain an underlay layer located and affixed between
the bottom surface of the print layer and the top surface of the
core.
The present invention further relates to a method of making a
thermoplastic laminate plank and involves the step of processing
(e.g., extruding) at least one thermoplastic material into the
shape of a core and optionally affixing a laminate on the core,
wherein the laminate can comprise a print layer, an overlay layer
affixed to the top surface of the print layer, and optionally an
underlay layer affixed to the bottom surface of the print
layer.
Also, the present invention relates to a method of making a
thermoplastic plank by printing a design directly on the top
surface of the plank using any number of printing techniques, such
as gravure printing, transfer printing, digital printing, Flexo
printing, screen printing, and the like. The method can also
include applying a protective coating on top of the printed design,
such as a polyurethane type coating with or without wear resistant
particles in the coating. The top surface of the plank can also be
treated or formed to have a textured finish such as a roughed,
grooved, cross-hatched, striated, pitted, cracked, or wood grain or
streak texture. In addition, decorative foils or printed overlays
can be affixed to the top surface of the plank and then covered by
a protective coating(s).
A further embodiment of the present invention relates to making a
thermoplastic plank for flooring by co-extrusion techniques, which
involves extruding at least one thermoplastic material into the
shape of the core and also extruding a layer containing at least
one thermoplastic material with one or more pigmented compounds on
top of the extruded core, wherein the layer simulates a design,
such as wood grain or marble.
The present invention also relates to thermoplastic planks having
the above-described characteristics.
It is to be understood that both the forgoing general description
and the following detailed description are exemplary and
explanatory only and are intended to provide further explanation of
the present invention, as claimed.
The accompanying drawings, which are incorporated in and constitute
a part of this application, illustrate several embodiments of the
present invention and together with the description serve to
explain the principles of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram showing an end view of one embodiment
of a thermoplastic laminate plank of the present invention.
FIG. 2 is a schematic diagram showing a side view of a spline
design which can be used to connect together the planks of the
present invention.
FIG. 3 is a schematic diagram of a sectional view showing another
embodiment of a thermoplastic laminate plank of the present
invention.
FIG. 4 is a schematic diagram showing a groove design for a
connector useful in connecting the planks of the present
invention.
FIGS. 5 and 6 are schematic diagrams showing end views of
additional embodiments of the thermoplastic laminate plank of the
present invention.
FIG. 7 is a schematic diagram showing an end view of an additional
embodiment of the thermoplastic plank of the present invention.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
In general, the present invention relates to a thermoplastic
laminate plank which contains a core comprising at least one
thermoplastic material. This core has a top surface, a bottom
surface, and at least four sides or edges. Located or affixed on
the top surface of the core can be a print layer having a top
surface and a bottom surface. Optionally located or affixed onto
the top surface of the print layer is an overlay layer having a top
surface and a bottom surface. The thermoplastic laminate plank of
the present invention can optionally further include an underlay
layer which is located and affixed between the bottom surface of
the print layer and the top surface of the core.
In more detail, the core in the thermoplastic laminate plank is
made of at least one thermoplastic material. Generally, any
thermoplastic material, combinations thereof, alloys thereof, or
mixtures of two or more thermoplastics can be used to form the
core. Generally, such thermoplastic materials include, but are not
limited to, vinyl containing thermoplastics such as polyvinyl
chloride, polyvinyl acetate, polyvinyl alcohol, and other vinyl and
vinylidene resins and copolymers thereof; polyethylenes such as low
density polyethylenes and high density polyethylenes and copolymers
thereof; styrenes such as ABS, SAN, and polystyrenes and copolymers
thereof, polypropylene and copolymers thereof, saturated and
unsaturated polyesters; acrylics; polyamides such as nylon
containing types; engineering plastics such as acetyl,
polycarbonate, polyimide, polysufone, and polyphenylene oxide and
sulfide resins and the like. One or more conductive polymers can be
used to form the plank, which has applications in conductive
flooring and the like. The thermoplastic polymers set forth in Kirk
Othmer (3.sup.rd Edition, 1981) at pp. 328 to 848 of Vol. 18 and
pp. 385 498 of Vol. 16, (incorporated in their entireties by
reference herein) can also be used as long as the resulting plank
has sufficient strength for its intended purpose.
Preferably, the thermoplastic material is a rigid polyvinyl
chloride but semi-rigid or flexible polyvinyl chloride may also be
used. The flexibility of the thermoplastic material can be imparted
by using at least one liquid or solid plasticizer which is
preferably present in an amount of less than about 20 phr, and more
preferably, less than 1 phr. A typical rigid PVC compound used in
the present invention to form the core can also include, but is not
limited to, pigments, impact modifiers, stabilizers, processing
aids, lubricants, fillers, wood flours, other conventional
additives, and the like.
The thermoplastic polymer compound to be processed can be in
powder, liquid, cubed, pelletized and/or any other extrudable form.
Also, the thermoplastic polymer can be virgin, recycled, or a
mixture of both. Furthermore, the thermoplastic material can be
incorporated with a blowing agent(s) or a mechanically injected gas
during the extrusion process to make a cellular foam structure
core.
The thermoplastic material used to form the core, which is
preferably polyvinyl chloride, is preferably a suspension grade or
mass polymerization grade homopolymer resin having a preferred
molecular weight as reflected by an inherent viscosity of from
about 0.88 to about 1.0 inherent viscosity. In general, a higher
molecular weight polymer is preferred from the standpoint of
processing stability and preferably the molecular weight
distribution and particle size distribution are narrow in order to
provide a good balance between processability and properties. Also,
high porosity and uniform porosity of the resin particles are
preferred to optimize compounding and processing aspects, including
the fast and uniform absorption of any stabilizer that is present
as well as other ingredients during compounding.
Preferably, the thermoplastic material used to form the core is a
rigid PVC powder compound that has good impact strength, ease of
processing, high extrusion rate, good surface properties, excellent
dimensional stability, and indentation resistance.
The preferred thermoplastic polymer used to form the plank is a
polyvinyl chloride from The Geon Company designated
X150-206-050-02, which has the following formula:
TABLE-US-00001 FORMULATION PARTS BY WEIGHT Extrusion Grade PVC
(0.88 0.96 IV) 100 Tin Mercaptide Stabilizer 2 4 PVC Acrylic
Processing Aid 1 3 Filler 10 30 Impact Modifier (Acrylic) 3 10
Lubricant Package 2 5 Pigment 1 5
The polyvinyl chloride preferably has the following properties:
TABLE-US-00002 GEON COMPOUND ASTM METHOD 87150 Type Powder Cell
Classification D1784 13344-C Specific Gravity 0.2 D792 1.45
Hardness-Durometer Shore D 3 D2240 82 Tensile Properties - Strength
PSI D638 6000 Tensile Properties - Modulus PSI D638 390000 Flexural
Properties - Strength PSI D790 11000 Flexural Properties - Modulus
PSI D790 370000 Heat Deflection Temperature F. D648 160 Unannealed
@ 1.82 MPa (264 PSI) Coefficient of Linear Expansion D696 3.4
.times. 10.sup.-5 in./in. F Notched IZOD Ft.lb./in. of notch @ D256
3 23 C. (73 F.) Impact Properties - Drop Impact D4226 1.0 in.lb/mil
@ 375 F. melt T. 1/4'' Dart H.250 Method A 1.0 1/4'' Dart H.250
Method B 1.0 1/8'' Dart H.125 Method A 1.0 1/8'' Dart H.1250 Method
B
Generally, this compound will have a melt temperature of from about
360 to about 390.degree. F. Preferably, a stabilizer is also
present in the thermoplastic formulation that forms the core. A
preferred stabilizer is a butyl tin mercaptide stabilizer. In
addition, an impact modifier is also preferably present and
preferred impact modifiers are acrylic-based from Rohm and Haas, an
EVA-based impact modifier known as Elvaloy.TM. from DuPont; and
others such as chlorinated polyethene and acrylonitrile butadiene
styrene, and the like.
In addition, the thermoplastic formulation preferably contains at
least one processing aid which is preferably an acrylic based low
molecular weight resin such as Acryloid K-125 or K-175 from Rohm
and Haas. Also, at least one lubricant is preferably present and
more preferably an internal lubricant and an external lubricant.
Preferred internal lubricants, which act internally to alter the
cohesive forces amongst the polymer chains that results in lower
melt viscosity without reducing the strength properties of the
resin, are metallic stearates such as calcium and zinc salts of
stearic acid. External lubricants, which act externally to prevent
resins from sticking to hot metal processing machinery by reducing
friction between the surfaces, are preferably low-melting
paraffins. Fillers are preferably added to the thermoplastic
formulation to reduce product cost and to improve impact
properties. While any filler can be used as long as it is
compatible with the thermoplastic resin, typical fillers include,
but are not limited to, calcium carbonate.
The thermoplastic core can be made of a thermoplastic resin and a
surface roughening agent, if a rough top surface of the core is
desired. Surface roughening agents can impart a non-slip surface to
the core or provide a rough surface that is more receptive to some
adhesives than a smooth surface would be. Exemplary surface
roughening agents include powdered materials having particle sizes
of about 1000 microns or less, and may comprise silicon glass
particles, pigments, TEFLON.RTM. powders, flour, cornstarch,
siliconized glass powders, and micronized cellulosic powders. Inert
powders are preferred, including TEFLON.RTM. powders, TEFZEL.RTM.
powders, KYNAR.TM. powders, polypropylene micropowders, and
TULLANOX.TM. micropowders. The surface roughening agents can be
mixed into the thermoplastic melt before the planks are extruded or
applied to the surface of the extruded plank while hot, so as to
become affixed to the surface.
Preferably, the thermoplastic core is rigid in nature and has the
following range of preferred properties: impact resistance, static
load resistance, indentation resistance, moisture insensitivity,
pre-profiled configuration, and the like.
While the core can be made in a number of ways, preferably the core
is formed by an extrusion process wherein the thermoplastic
material along with any other optional ingredients are blended
together and are then fed into an extruder by a feeder wherein the
extruder with the application of heat and auger action melts the
thermoplastic material to the extent that it is eventually fed
through a die, wherein the die is in the shape of the core.
In more detail, the extrusion process permits a) an economically
feasible design by designing a profile with cavities inside the
structure and b) a highly versatile method of achieving the
complicated profile design of the preferred plank without
additional machining afterwards for the tongue and groove, for
instance. While any extruder can be used which can extrude the
desired design of the plank for thermoplastic materials, preferably
the extruder is one from American Maplan corporation such as model
TS-88 which has the ability to process rigid PVC profiles with a
maximum output capacity of about 900 lb/hr, based upon a compound
bulk density of 37 lb/ft.sup.3. The TS-88 is a twin screw extruder
which has a barrel heating section and a cooling section as well as
a vacuum system. In the extruder, there can be 12 temperature zones
with 6 for cooling and a temperature control system.
The dimensions of the core can practically be any shape or size as
long as such material can be extruded as one piece or multiple
pieces. For instance, the core preferably has a thickness of from
about 3 mm to about 50 mm, a width of from about 2 cm to about 60
cm, and a length of from about 30 cm to about 215 cm. The core can
preferably have a square or rectangular shape. An exemplary core
has a width of up to seven inches (18 cm) or more and a length of
about 72 inches (183 cm) or more. An exemplary rectangular core has
a width of about five inches (13 cm) and a length of about 72
inches (183 cm). Also, the top surface of the core can optionally
have a textured surface on the top surface as part of the core
which is extruded through the die. The top surface of the plank can
also be treated or formed to have a textured finish such as a
roughed, grooved, cross-hatched, striated, pitted, cracked, or wood
grain texture. A mechanical embossing roller can be located behind
the cooling calibrator and after the extrusion die to achieve
surface texturing of the extruded core. Any variety of textures can
be created by this method on the core such as wood grains and the
like.
Also, as an option, the core can be 100% solid or can have one or
more cavities or cells which are located between the upper and
lower surfaces of the core. While the cavities are optional, the
cavities are preferred since they reduce the amount of
thermoplastic material used and create a lighter weight product.
The cavities or cells which can be part of the extruded core
preferably have cavities having dimensions of from about 3 mm to
about 16 mm in height, by about 6 mm by about 20 mm in width, and
can be separated by solid thermoplastic material walls having
thicknesses of from about 1.0 mm to about 3.02 mm. The optimal
dimension of cavities is dependent upon the requirement of the
product to withstand the potential impact force of falling objects.
The cavities which are preferably present can be of any
cross-sectional shape such as rounded, oval, triangular, or
rectangular. These cavities or cells preferably exist across the
entire distance of the core as shown in FIGS. 1, 5, and 6.
Preferably, each cavity extends longitudinally along the entire
length of the plank, although the cavities can instead extend
latitudinally along the entire width of the plank. Preferably, the
cavities extend in the direction of extrusion of the thermoplastic
plank material.
Another advantage is that wires, cables, fiber optics, and/or
piping can be run through the cavities which makes installation of
wiring and piping quite easy without the necessity of putting holes
through walls, or running wires underneath the floor or in the
ceiling. Further, if necessary, holes can be drilled through the
thermoplastic material separating one cavity from another in order
to have the wire or piping go in a perpendicular direction when
necessary. Alternatively, for certain thermoplastic core pieces,
the cavities can be run in a perpendicular direction from the
remaining pieces in order to accommodate the direction that wiring
or piping may take when being placed in a room.
According to some embodiments of the invention, electric wires,
phone lines, cable television lines, speaker wires, heating
elements, hot or cold air conduits, or the like can be integrally
extruded within the thermoplastic material of each plank and
suitable terminals or connectors, such as pin and hole connectors,
can be formed on the ends of the planks and connected to each wire,
conduit, or the like. In this manner, a series of planks can be
pieced together and carry, for example, a speaker signal from one
end of a floor to another end of the floor. Heated or cooled floors
can be manufactured having connecting conduits through which
adjacent planks can carry hot or cold air.
The cores which form the plank are preferably all made from the
same die design and thus they are uniform in appearance. Also, the
cavities which are preferably present in the core align with the
cavities in respective core pieces. Dowels or other equivalent
material can be inserted into the cavities at the short end of the
plank in order to join an adjacent plank to create a tight seal at
each seam. The ends of the planks can have formed therein grooves
for receiving a toothed spline or other connecting member so that
the ends of adjacent planks can be joined together in the same
manner, or in a similar manner, as the side edges of the planks are
joined. The end grooves can be cut or otherwise formed in the
extruded planks after extrusion. One end of each plank can be
provided with one or more alignment or centering pins while the
opposite end of each plank can be provided with one or more
recesses, holes, or openings for receiving an alignment pin from an
adjacent plank. These types of coupling systems, though optional,
will further ensure a very secure tight fitting floating floor or
other surface covering.
Though not necessary, the ends of the plank as well as the tongue
and/or groove can have a bonding agent applied to these locations
in order to seal or bond the planks together. Surprisingly, the
inventors have discovered that sealant compositions such as
tetrahydrofuran have the ability to actually work as a bonding
agent to join the planks together. In one of the examples that
follows, the results show that by using tetrahydrofuran or
compositions like tetrahydrofuran, the joints of the planks which
have been attached with the use of this composition leads to the
formation of a bond between the planks and increases the overall
bond strength of two adjoining boards significantly. The use of
this bonding agent can be used not only with the planks described
above but with all thermoplastic planks, provided the bonding agent
is capable of solvating or dissolving the particular plastics to
form a chemical and/or mechanical bond. One advantage of using a
bonding agent like tetrahydrofuran is that it is effective, it is
simple to use, and leaves no residue on the surface after
evaporation. Thus, no adhesive marks are left on the surface of the
planks. In addition, applying such bonding agents like
tetrahydrofuran is quite easy since it can be applied by brush or
spray or applicator tip using gravity or other force such as
squeezing an applicator bottle, and any excess is easily removed
unlike the application of some adhesives for tiles and the like.
Other examples of other suitable bonding agents which have this
ability to bond the thermoplastic planks include, but are not
limited to, methylene chloride and ketones and the like. Examples
of ketones include, but are not limited to, methyl ethyl ketone,
methyl amyl ketone, dipropyl ketone, methyl isobutyl ketone,
n-methyl pyrrolidone, dimethyl formamide, cyclohexanone,
nitrobenzene, and the like.
Another optional aspect of the core is the presence of a groove
and/or a tongue design on preferably two or more sides or edges of
the core wherein the sides or edges are opposite to each other.
While the core design can have a tongue design on one edge and a
groove design on the opposite edge, it is preferred that both edges
which are opposite to each other have a groove design. This tongue
and/or groove design on the core can be formed as part of the
extruded core. The tongue or groove can have a variety of
dimensions but preferably the groove which is present on two,
opposite edges has internal depth dimension of from about 5 mm to
about 12 mm and a height of from about 3 mm to about 5 mm. The
bottom width of the side having the groove is slightly shorter than
the upper width of the same side to ensure no gap exists between
planks after butting together. In other words, the bottom lip of
the groove is slightly narrower than the top lip, ensuring the top
lip of laterally-adjoining planks will meet before the bottom lips.
This ensures no visible surface gap. In addition, it is preferred
that the groove have teeth located on the upper surface and lower
surface of the groove to receive an interlocking tongue, wherein
the tongue is a separate component which will be described later.
The teeth which can preferably be present as part of the extruded
groove forming part of the extruded core are preferably from about
0.2 mm to about 1.2 mm in size for each tooth and having an angle
of from about 30 to 45 degrees with a backward bite enabling easier
insertion than removal of the tongue portion. A preferred design is
set forth in FIGS. 3 and 4.
Also, as an option, any edge, and preferably the edges which
preferably have the tongue and/or groove, are preferably tapered or
beveled so that when two cores are brought together for attachment,
a valley or V-shaped recess is formed. Preferably, the tapered or
beveled edges are at an angle of from about 15.degree. to about
55.degree., and more preferably at about a 17.degree. angle. Also,
the length of the beveled or tapered edge is about 2.0 mm to about
7.0 mm on each core piece. A preferred design is set forth in FIG.
3.
As another option, the core can have located on its bottom surface
any number of bottom feet which are preferably pieces of rubber or
thermoplastic material which are attached to the bottom surface of
the core. Preferably, the bottom feet are thermoplastic material
and more preferably are soft thermoplastic material which are
post-extruded onto the bottom surface of the plank. While the
bottom feet can have any dimensions, preferably the bottom feet
have an outer dimension of from about 1.0 mm to about 5.0 mm. The
bottom feet provide numerous functions such as increasing the soft,
cushion feeling of the plank to improve foot comfort level and also
reduces the problems associated with sub-floor or substrate
imperfections. The bottom feet can also assist in controlling sound
transmissions, and thus have sound deadening properties. Also, the
bottom feet ensure that migration from any mold, mildew, and/or
stain which may be part of the sub-floor or substrate can be
minimized if not eliminated by the bottom feet.
As an additional option, the product with bottom feet can be
installed up side down to make a slip resistance floor for such
applications as escalators or stairways. The bottom feet are
located on the bottom surface of the core and preferably appear as
a series of raised parallel rods running longitudinally along the
bottom of the plank. These may be formed by post-extruding soft
polymeric rods into depressed grooves present in the extruded core
plank bottom. These raised feet extend outward from the bottom of
the plank and act to support the core above the subfloor or
substrate. Typically, the post extruded material extends beyond the
bottom surface from the core by about 10 mils (0.25 mm) to about 75
mils (2.0 mm), and more preferably from about 25 mils (0.65 mm) to
about 50 mils (1.3 mm). FIGS. 1, 3, 5, and 6 further show
embodiments of how the post extruded rods of thermoplastic material
can serve as a support mechanism.
With respect to the laminate on top of the core, a print layer is
affixed to the top surface of the core, wherein the print layer has
a top surface and a bottom surface. The print layer preferably is
an aminoplast resin impregnated printed paper. Preferably, the
print layer has a printed design. The printed design can be any
design which is capable of being printed onto the print layer. The
print layer is also known as a decor print layer. Generally, the
print layer can be prepared by rotogravure printing techniques or
other printing means such as digital printing. Once the paper has
the design printed on it, the paper is then impregnated with an
aminoplast resin or mixtures thereof. Preferably the aminoplast
resin is a blend of an urea formaldehyde and a melamine
formaldehyde.
The print paper, also known as the Deco paper, preferably should
have the ability to have liquids penetrate the paper such as a
melamine liquid penetrating in about 3 to 4 seconds and also
maintain a wet strength and even fiber orientation to provide good
reinforcement in all directions. The print paper used doesn't need
to impregnate with the resin (this is optional), but instead relies
on slight resin migration from the adjoining layers during the
lamination process (applying heat and/or pressure to laminate all
layers to one). Preferably, the resin used for the impregnation is
a mixture of urea formaldehyde and melamine formaldehyde resins.
Urea formaldehyde can contribute to the cloudiness of the film that
is formed and thus is not preferred for dark colors and the
melamine resin imparts transparency, high hardness, scratch
resistance, chemical resistance, and good formation, but may have
high shrinkage values. Combining urea resins with melamine resins
in a mixture or using a double impregnation (i.e., applying one
resin after another sequentially) provides a positive interaction
in controlling shrinkage and reducing cloudiness. Preferably, the
type of paper used is 75 g/m.sup.2 weight and having a thickness of
0.16 mm. The saturation of the coating preferably is about 64
g/m.sup.2.
Located optionally on the top surface of the print layer is an
overlay. The overlay which can also be known as the wear layer is
an overlay paper, which upon being affixed onto the print layer, is
clear in appearance. The overlay paper is preferably a high
abrasive overlay which preferably has aluminum oxide embedded in
the surface of the paper. In addition, the paper is impregnated
with an aminoplast resin just as with the print layer. Various
commercial grades of high abrasive overlays are preferably used
such as those from Mead Specialty Paper with the product numbers
TMO 361, 461 (70 gram/m.sup.2 premium overlay from Mead), and 561
wherein these products have a range of Taber values of 4000 to
15000. The type of paper preferably used has a weight of about 46
g/m.sup.2 and a thickness of about 0.13 mm.
With respect to the print layer and the overlay, the amount of
aminoplast resin is preferably from about 60 to about 140 g/m.sup.2
and more preferably from about 100 to about 120 g/m.sup.2.
As an option, an underlay can be located and affixed between the
bottom surface of the print layer and the top surface of the core.
Preferably the underlay is present and is paper impregnated with an
aminoplast resin as described above with respect to the print layer
and overlay. Preferably, the underlay is Kraft paper impregnated
with aminoplast resins or phenolics and more preferably phenolic
formaldehyde resin or melamine formaldehyde resin which is present
in an amount of from about 60 g/m.sup.2 to about 145 g/m.sup.2 and
more preferably from about 100 g/m.sup.2 to about 120 g/m.sup.2
paper. The type of paper used is preferably about 145 g/m.sup.2 and
having a thickness of about 0.25 mm. The underlay is especially
preferred when extra impact strength resistance is required.
Preferably, the thermoplastic laminate plank can be prepared by
extruding the core as described above and forming a laminate
comprising the overlay affixed to the top surface of the print
layer and optionally the underlay layer which is affixed to the
bottom surface of the print layer. This laminate can be prepared,
for instance, by any process customarily used to manufacture
laminate films such as a continuous double belt press. In general,
the underlay, if used, the print layer and the overlay can be fed
into a continuous double belt press that serves as a laminating
calendar. Preferably, the continuous operation is an isobaric
system wherein pressures can go as high as 30 bar and the line
speed can be up to 20 meters per minute. The pressure zone length
is about 2 3 meters. In this continuous double belt press system,
the isobaric system provides a steady uniform pressure effect on
each point of the treated surface of the laminate. Embossing of the
laminate can be accomplished by embossed release paper or the belt
of the double belt press can be embossed to produce surface
textures. In a continuous double belt press, the simultaneous
heating of the laminate with proper dwell time and pressure forms
the laminate film which can then be rolled up for subsequent
application. Once the laminate is formed it can be applied onto the
core and is preferably affixed by any means, such as with an
adhesive. Preferably the adhesive is a hot melt adhesive such as a
hot melt glue like hot melt polyurethane glue.
The hot melt adhesive, such as the hot melt polyurethane adhesive,
is preferably applied to the back surface of the laminate film at a
preferred temperature of from about 250.degree. F. to about
300.degree. F., more preferably from about 250.degree. F. to about
275.degree. F. These temperatures may vary slightly depending upon
the adhesive. The application of the hot melt adhesive to the
laminate can be done by a direct roll coater. The laminate with the
adhesive on the back surface can then be heated to an adequate
temperature to soften the laminate and allow the laminate to form
to the profile of the thermoplastic core and thus be affixed
permanently. The typical wrapping machine is designed to hold the
laminate to the contour of the thermoplastic plank as it is being
cooled to below about 90 to about 100.degree. F. The thickness of
the application of the adhesive can have an effect on the impact
resistance of the finished product. If the application of the
adhesive is too thick, an impact may cause the laminate to become
brittle and crack. A thin application enables the laminate to flex
less during impact and minimize the damage. Application of the
adhesive is preferably made at a rate of from about 5 to about 15
grams per square foot (g/ft.sup.2) and more preferably from about 4
to about 8 g/ft.sup.2. A preferred hot melt adhesive is
Ever-Lock.RTM. 2U145/2U230 modified polyurethane adhesive reactive
hot melt from Reinhold Chemicals, Inc.
As described earlier, the various laminate planks of the present
invention can be connected together by a tongue piece or spline or
snap connector. A separate spline or snap connector is a separate
piece and is especially effective when a groove is present on two
opposite sides or edges of the thermoplastic laminate plank. The
snap or tongue piece can be inserted into one groove and is long
enough to extend outside the groove and fit into a respective
groove of another thermoplastic laminate plank in order to connect
the two pieces together. Preferably, the tongue piece or snap
connector is a co-extruded material that is made of a rigid
thermoplastic material such as polyvinyl chloride or polyvinyl
chloride/rubber blends in the central portion and a soft
thermoplastic material such as soft polyvinyl chloride at the top
and bottom surface of the snap connector in order to be flexible
when inserted into the groove so as to securely engage the teeth
portions of the groove in the preferred embodiment.
The snap connector is designed for ease of installation. To achieve
this objective is to mechanically interlock two planks together
with a connector without using glue. The connector is to fit into
the side grooves of two adjoining planks. The purpose of the snap
connector includes holding the planks together and preventing water
pooled on the top of the joint from penetrating totally through the
joint and wetting the subfloor or surface under the planks.
The snap connector, also known as a spline, has a width large
enough to allow the teeth in each adjoining groove to grip the
connector satisfactorily, but the snap connector must be narrower
than the combined groove depths of the adjoining planks to allow
the tops of the planks to come together (See FIG. 3). Thus, the
snap connector should be as wide as possible to provide maximum
grab surface, but should be narrow enough to allow the top surfaces
of the adjoining planks to meet. The width of the snap connector
would preferably range from about 0.007 to about 0.013 inches less
than the nominal groove depth to allow for processing variability.
To increase the "bite" of the teeth in the groove onto the surfaces
of the connector, the top and bottom surfaces of the connector may
be made of a softer material than the core of the connector. This
material may be comprised of plasticized vinyl, a vinyl rubber
blend, and the like. One such embodiment contains a hard inner core
made of GEON 8700 compound with a total thickness of about 2 mm to
about 3 mm with a top and bottom surface made of GEON 8602 product
with thickness of from about 1.3 mm to about 3 mm for each
surface.
The snap connector may have a variety of configurations. In one
such configuration, the top and bottom surfaces are flat. This will
allow the teeth in the top and bottom surfaces of the adjoining
grooves to grip the connector. The thickness of the connector is
determined by two factors. The thicker the connector, the more
pressure the groove teeth will apply. However, the connector can
not be too thick or the force needed by the installer to drive the
adjoining planks together will be too high. In the case of the
connector design with flat top and bottom surfaces, the connector
thickness will range preferably to no more than about 0.13 mm to
about 0.26 mm more than the groove opening of the plank into which
it is being inserted.
Another configuration includes sets of teeth running longitudinally
down the length of the connector. These teeth may appear on both
top and bottom surfaces or only on one surface with the other
surface being flat. The teeth preferably will be configured to
slant in the opposing direction to the teeth in the plank groove,
thus allowing an "interlocking effect".
Due to the flexibility of the teeth, a greater extrusion tolerance
for the side groove of the plank can be accommodated. The total
thickness of the connector may be in excess of 0.9 mm greater than
the plank groove opening and the force required for installation is
still acceptable. The flexibility of the teeth in the connector
will depend on the material of which it is made. One such
embodiment contains a hard inner core made of GEON 8700 compound
with a total thickness of about 2.8 mm and a top and bottom surface
made of GEON 8602 product with thickness of about 0.76 mm for each
surface. The top and bottom surfaces can contain a soft flat layer
of about 0.25 mm from which teeth 0.5 mm long protrudes.
Another configuration allows depressed serrated "valleys" running
longitudinally in the direction of the connector. These depressed
serrations will allow teeth of the grooves in the plank to more
easily mate into the connector.
In the present invention, while each of the thermoplastic laminate
planks can be affixed to the sub-floor or substrate, it is
preferred that the thermoplastic laminate planks be attached only
to each other through the groove system such that there is a
floating floor system. This promotes fast and easy laying of the
floor system.
With the thermoplastic laminate planks of the present invention,
the present invention achieves many benefits and advantages, such
as moisture resistance, mechanical properties such as impact
strength, resistance to indentation and gouges, and beneficial
acoustical properties. Further, the laminate plank system of the
present invention can be used in any environment, dry or wet,
indoor or outdoor since it is not susceptible to moisture damage or
distortion. In an embodiment of the present invention, the planks
are less sensitive to the combined effects of temperature and
humidity than is the standard laminate product. As a result, the
need for T-moldings to act as expansion and contraction areas of
the floor can generally be eliminated. These T-moldings are not
only unsightly, but can act as tripping hazards. By the elimination
of T-moldings/expansion joints in the walkway, the present
invention allows the use of the floor in commercial applications.
In an embodiment, the present invention expanded only one fifth as
much as a standard laminate product under identical conditions.
These conditions take the product from ambient room conditions to
conditions of 100% relative humidity and 90.degree. F. Standard
expansion joints for laminate are typically placed every 30 feet.
Thus, a hallway of 150 feet would be feasible without an expansion
joint according to the present invention.
A second study shows that by post conditioning the planks, such as
at 240.degree. F. for varying times of from 20 to 40 seconds, the
planks may be rendered even more stable. This treatment is referred
to as thermal balancing. Results are described in the table
below.
TABLE-US-00003 Growth in Growth in Description of Flooring Width**
Length** Plank #1* 0.03% 0.03% Plank #2* 0.03 0.03 Plank #3* 0.04
0.03 Laminate Plank (Comparison) 0.10 0.20 (Commercial product)
*present invention **Conditions start at ambient room conditions.
Product expands during change to 90.degree. F. and 100% RH.
Also, in the preferred embodiment of the present invention, the
installation method used as a result of the unique designs of the
thermoplastic laminate planks of the present invention, preferably
eliminates the glue needed for tongue and groove connections.
In the preferred embodiment of the present invention, the
installation method utilizes the unique design of the product to
eliminate the need for glue used in tongue and groove
connections.
Furthermore, the installer has options for installing the
thermoplastic laminate plank product. In one method, a floating
floor installation method can be utilized. In this method, no
adhesive is applied to bond the product to the subfloor surface.
The benefits of this method have been described earlier.
In a second method, a full-spread adhesive is applied between the
underside of the product and the sub-floor surface. This provides
the advantages of added dimensional stabilization and sound
deadening. Both of these properties would be beneficial in
commercial applications.
In addition, the excellent moisture resistance and sound deadening
qualities of this product can eliminate the need for underpadding,
though use of underpadding is an option.
A further embodiment of the present invention relates to a
thermoplastic plank which comprises the same plank described above
but, in lieu of a laminate on top of the plank, a design is printed
directly on the top surface of the plank using any number of
printing techniques such as gravure printing, transfer printing,
digital printing, flexo printing, and the like. Or, a printed
thermoplastic film (e.g., PVC) or a wood veneer and the like can be
laminated to a thermoplastic plank. A protective coating can then
be placed on top of the printed design. Any type of protective
coating or wear layer can be used such as a polyurethane type
coating with or without wear resistant particles in the coating.
Thus, a thermoplastic plank would comprise a core comprising at
least one thermoplastic material where the core has a top surface
and bottom surface as well as opposing sides and a printed design
directly on the top surface of the plank and optionally at least
one protective coating on top of the printed design. The top
surface of the plank as described earlier, can have a textured
surface as described above.
This type of thermoplastic plank can be made by extruding at least
one thermoplastic material into the shape of the core and then
printing a design directly on the top surface of the plank and then
optionally applying at least one protective coating on top of the
printed design and curing the protective coating. The protective
coating can be applied by conventional techniques, such as curtain
coater, direct roll coater, differential roll coater or air knife
coater or spray apparatus.
In another embodiment of the present invention, a thermoplastic
plank for surface coverings, such as flooring, has a thermoplastic
core as described above in the other embodiments and a extruded
layer on the top surface of the core wherein this extruded layer
comprises at least one thermoplastic material with one or more
pigmented compounds. This extruded layer on top of the extruded
core can simulate various designs such as wood grain and the
like.
The thermoplastic plank in this embodiment can be made by
co-extrusion techniques which involve extruding at least one
thermoplastic material into the shape of a core and extruding
either simultaneously or subsequently a layer containing at least
one thermoplastic material with one or more pigmented compounds on
top of the extruded core.
Another embodiment involves a thermoplastic plank having the same
design as described above with a printed polymeric film, such as a
PVC film placed on the top surface of the extruded core. The
printed polymeric film can be a polymeric film having a printed
design on the film wherein the film would preferably be from about
10 to about 20 mil thick. One or more wear layers or protective
coatings can be placed on top of the printed polymeric film. The
polymeric film can be placed on top of the extruded core by typical
lamination techniques such as heating the printed film, then
pressing the film to the extruded core to bond them together, or
using glue to bond them together.
In more detail and with reference to the Figures, the Figures show
various aspects of several embodiments of the present invention. In
each of FIGS. 1 6, the length measurements shown are in units of
inches and angle values are shown in degrees. For each measurement
set forth in decimal form, the tolerance is +/-0.005 inch per
measurement. For each measurement set forth in fraction form, the
tolerance is +/- 1/16 inch per measurement. For each angular
measurement, the tolerances is +/-0.5.degree..
With reference to FIG. 1, FIG. 1 represents a schematic diagram of
an end view of one embodiment of the thermoplastic plank. FIG. 1 is
a perspective view looking at the front edge of the thermoplastic
plank wherein the groove (76) would run along each longitudinal
edge of the plank. The spline or tongue (64) is inserted along the
length of each groove (76). (72) points to the edges of the spline
having the groove whereas (68) points to the lower or bottom
surface of the plank and (70) points to the top surface or the
surface that typically but optionally receives the print layer and
the like. (62) refers to the feet or strips of post-extruded
material which extend along the bottom surface of the core from the
front edge to the back edge. As can be seen in FIG. 1, typically
these post extruded lines of thermoplastic material act as a
support mechanism and typically run parallel in the same parallel
direction as the cavities (60). Preferably, and as shown in the
embodiments in FIG. 1, the edge side of the plank which has a
groove is typically tapered or beveled as shown at (78). The
cavities (60) are shown in FIG. 1 as having rectangular
cross-sections. The cavities extend longitudinally along the length
of the plank, preferably along the entire length of the plank from
one end to an opposing end.
In the embodiment of FIG. 1, the overall width (from left to right
in the view shown) of the plank is 7.000 inches (178 mm) not
including the splines or tongues 64 shown connected at each end of
the plank. The length of the plank (not shown) is 72 inches (1829
mm). The width of each cavity (shown from left to right) is 0.335
inch (8.51 mm). The vertical dimension of the upper and lower wall
thicknesses above and below each cavity is 0.070 inch (1.78 mm)
each. The height (in a vertical dimension) of each cavity is 0.215
inch (5.46 mm). The width (from left to right) of the vertically
disposed side walls between adjacent cavities is 0.060 inch (1.52
mm) with the exception of the outermost side walls adjacent the
grooves 76, which each have a width of 0.116 inch (2.95 mm).
Referring to FIG. 2, FIG. 2 is a representation of one type of
spline or tongue (64) that can be used in one embodiment of the
present invention. As can be seen in FIG. 2, the preferably soft
material (82) such as PVC is located on the top and bottom surface
of the spline or tongue in order to ensure a tighter fit with the
groove of the thermoplastic plank.
The spline design preferably has a thickness of from about 3 mils
(0.13 mm) to 5 mils (0.26 mm) thicker than the groove of the plank.
If the spline is too thick, it can open the groove and cause edge
peaking. If the spline is too thin, it does not effectively engage
with the teeth in the groove. The edges of the spline or tongue
(64) are tapered or beveled as shown at (80) in order to ensure
that the tongue can be inserted into the groove.
In the embodiment shown in FIG. 2, the overall width of the spline
or tongue 64 (from left to right) is 0.500 inch (12.7 mm) and the
overall height is 0.180 inch (4.57 mm).
The thickness of the soft material 82 shown on the top and bottom
of the spline or tongue is 0.023 inch (0.58 mm). For each of the
top and bottom surfaces of the spline, the respective surface is
made up of 0.064 square inch (1.63 mm) of a rigid polyvinylchloride
(PVC) material and 0.019 square inch of a soft polyvinylchloride
material. The angled corners of the spline or tongue 64 are each
angled about 30.degree. with respect of the flat top and bottom
respective adjacent surface of the spline or tongue 64.
FIG. 3 makes reference to a spline (64) which has teeth (90) on its
surfaces which engage the grooves (76) of the thermoplastic planks.
Further, as can be seen in FIG. 3, in a preferred embodiment, the
top surfaces of the plank form a V shape valley (88) and the top
edges of the adjacent planks touch each other whereas the bottom
edge portions of each respective plank are cut in order to have a
slightly shorter length and thus form a gap (86) which ensures that
the top ends (88) touch each other and do not leave any gaps on the
walking surface of the planks. Reference numeral (84) shows a top
layer, such as a print layer, a composite print layer, or the
like.
In the embodiment shown in FIG. 3, the width dimension of the gap
86 (from left to right) is 0.030 inch (0.76 mm). The thickness of
the top layer 84 shown in FIG. 3 is 0.015 inch (0.38 mm). The
surface area, viewed from the bottom, of the feet or strips 62 of
post-extruded material is 0.0048 square inch (0.122 mm) each and
they are made of a soft polyvinyl chloride material. The total
surface area, covered by feet or strips 62, of the bottom of either
plank shown connected in FIG. 3 is 0.0624 square inch (1.60 mm).
The two connected planks shown in FIG. 3, each have dimensions of
from about 7.0 inches in width and about 72 inches in length, and
each is provided with 13 feet or strips 62.
Referring to FIG. 4, FIG. 4 is a depiction of a groove (76) which
has receiving teeth (92) for a spline or tongue of the design shown
at (90) in FIG. 3. FIG. 4 further shows the post extruded lines
(62) on the bottom surface of the extruded plank as well as the
various angles and cuts of the cavity (60). Further, the beveled or
tapered edge (78) is shown in FIG. 4.
In the embodiment shown in FIG. 4, the foot 62 has a width of 0.075
inch, a height of 0.075 inch, and is housed in a corresponding
groove or hole that extends 0.050 inch into the bottom surface of
the flooring plank. As such, 0.025 inch of the foot extends past
the bottom surface of the plank. The cavity 60 shown in FIG. 4 has
an upper corner defined by a radius of curvature of 0.025 inch and
a bottom corner including a 45.degree. angle wall that intersects
with the side wall and the bottom wall of the cavity in radii of
curvature of 0.025 inch each. The beveled or tapered edge 78 shown
in FIG. 4 is angled in an amount of 17.degree. relative to the flat
top surface of the plank. The beveled or tapered bottom edge
opposite edge 78 is angled in an amount of 30.degree. relative to
the flat bottom surface of the plank. The receiving teeth 92 are
each 0.040 inch wide (from left to right) and each has a flat top
surface at its point that has a width of 0.008 inch. The gap
between opposing top and bottom teeth is 0.150 inch. The depth of
the groove 76, from the edge of the plank to the deepest part of
groove 76 (from left to right) is 0.270 inch and the depth from the
left edge of the plank to and including the last tooth within the
groove is 0.201 inch. The beveled or tapered edge 76 intersects
with the flat top surface of the plank 0.125 inch from the edge of
the plank.
FIGS. 5 and 6 represent various different widths of the plank but
generally show the same features as shown in FIG. 1 and the
reference numerals in FIGS. 5 and 6 represent the same features as
the corresponding numerals represented in FIG. 1.
The dimensions of the cavities and wall thicknesses of the
embodiment shown in FIG. 5 are substantially identical to the
dimensions shown in FIG. 1 with the exception that the overall
width of the plank shown in FIG. 5 is 3.000 inches as opposed to
7.000 inches for the width of the plank shown in FIG. 1. In
addition, the two vertical side walls adjacent each respective gap
76, herein referred to as the two outermost side walls, are 0.075
inch in width as opposed to 0.116 inch in width for the
corresponding outermost side walls of the embodiment shown in FIG.
1. The overall height of the plank shown in FIG. 5, from the flat
top surface to the flat bottom surface (excluding the feet or
strips 62) is 0.355 inch for the embodiment shown in FIG. 5.
For the embodiment shown in FIG. 6, the dimensions are
substantially identical to those dimensions shown in the embodiment
of FIG. 5, with the exception that the plank shown in FIG. 6 has an
overall width of 5.000 inches and each cavity has a width of 0.303
inch.
FIG. 7 depicts yet another embodiment of the thermoplastic plank
according to the present invention. FIG. 7 is an end view of an
embodiment wherein the extruded thermoplastic plank has a
substantially planar top surface (92), and a bottom surface (94)
having a plurality of channels formed therein, wherein each channel
(96) extends longitudinally from one end of the plank to the other
end of the plank. The channels can be U-shaped, u-shaped, or have
any other suitable cross sectional shape. The channels (96), when
the planks are in place on a floor, can house any of a variety of
electrical or signal-carrying wires, cables, cords, or conduits.
The plank is significantly lighter than a similar plank having the
same dimensions but without having the channels formed therein. A
flooring system made of such planks has a softer feel and a lighter
weight than an otherwise similar but solid plank. As shown in FIG.
7, a centering pin (98) and a pin receiving hole (100) are each
provided on both ends of the plank so that adjacent planks can be
aligned with each other in an end-to-end configuration.
The thermoplastic planks of the present invention can be used in a
variety of applications including, but not limited to, wall panels,
ceiling panels, flooring surfaces, decks, patios, furniture
surfaces, shelving, and other surface coverings or parts
thereof.
The present invention will be further clarified by the following
examples, which are intended to be purely exemplary of the present
invention.
EXAMPLES
Example 1
Compound:
In one case a PVC compound containing impact modifier, filler,
stabilizer and processing aids in the amounts below was extruded
through a profile die giving a hollow cross section as shown in
FIGS. 1, 5, and/or 6.
TABLE-US-00004 Ingredient Amount (phr) PVC Homopolymer 100 Thermal
Stabilizer 0.8 1.5 Processing Aid 0.5 1.0 Impact Modifier 3.0 4.0
Lubricant internal 0.6 1.0 external 1.1 1.5 Filler 20 35 TiO.sub.2
1.5 3.0 Barrel 1 Barrel 2 Barrel 3 Barrel 4 Barrel 5 Barrel
Temperatures, deg. 345 360 345 360 320 340 315 330 90 110 F. Oil
Temperature deg. F. (through screw) 285 300 Die 1 Die 2 Die 3 Die 4
Die 5 Die Temperatures, deg F. 345 360 360 370 360 370 380 390 370
380 Percent Load 63 75% Main RPM 950 1100 Output 356 550 pounds/hr
(163 250 kg/hr) Back Pressure 18.1 19.0 metric tons Melt Pressure
4,075 4500 psi Melt Temperature, deg. F. 385 390 Color Feeder 0.35
0.70 pounds/hr (setting of 5 for 0.35, setting of 10 for 0.70) Line
Speed 8.5 8.75 feet/min Calibration Unit: Vacuum 1 16 20 in Hg
Vacuum 2 17 20 in Hg Vacuum 3 12.5 15.0 in Hg Vacuum 4 off Puller
Force 3560 4000 pounds Water Temperature, .degree. F. 61 Pressure
at Cooling and Sizing, psi #1 40 mbar #2 40 mbar Clamping Pressure
at conveyor Front 40 45 psi Back 28 35 psi Counterbalance 33 40 psi
Specific Applications Wrapping Conditions: Layout of
line/Conditions:
A machine was used to form the HPL (High Pressure Laminate top
layer) onto the PVC Plank Base. The machine was called a "wrapping
machine" and is composed primarily of two main parts 1) a forming
action component to shape the HPL to the contour of the base, and
2) a clamping action component to retain the HPL shape onto the
base as the adhesive cools and strengthens.
In more detail: 1. PVC Planks were placed onto the line to be
conveyed through by rubber covered roller wheels. Speed of
conveyance was 35 50 feet per minute in this particular
application. In other applications, speeds may range as high as 120
fpm. 2. PVC Planks underwent surface treatment to raise surface
tension and improve the wetting of adhesive onto the surface. The
surface treatment unit which was from Corotec, 145 Hyde Rd,
Farmington, Conn., provided plasma jet treatment. The surface
tension was raised from 34 to 45+ dynes/cm. 3. HPL (laminate) top
layer, dispensed in a continuous roll, was treated with a
polyurethane hot melt adhesive, Reichold 2U145, available from
Reichold Chemicals, 2400 Ellis Rd, Durham, N.C. The adhesive was
heated to 237 degrees F. and rolled onto the back of the HPL layer
with a knurled roll. 4. The HPL was then mated to the PVC Plank,
and IR heat was directed onto the face of the HPL. Temperature on
the face of the PVC Plank was raised to 300.degree. F. 330.degree.
F., which softens the HPL enough to allow shaping. 5. The HPL was
shaped using rubber rollers onto the face of the PVC plank and down
the beveled edges of the plank. As such, this wrapping process
shaped the HPL to adhere to the topography of the plank onto which
it is being affixed. 6. Water spray quickly lowered the temperature
of the HPL/PVC Plank assembly to below 100.degree. F. (e.g., 94
.degree. F.). Rubber rollers continued to hold the HPL onto the PVC
surface while the assembly cooled further. This allowed the
adhesive to cool and strengthen, thereby permanently affixing the
HPL top layer to the PVC Plank lower layer. 7. Each individual
plank assembly was then separated from the following planks with a
force appropriate to make a sharp separation. Post-Treatment:
Mechanical Post-Treatment
The HPL/PVC Plank assembly was then finished with end cutting and
edge trimming procedures to cut the board ends square and trim the
laminate overhang flush to the base plank.
Thermal Post-Treatment
Due to the uneven top-side heating of the HPL/PVC Plank assembly
during shaping, the finished product can develop a "cup" distortion
where the top ends of the plank come closer together. In order for
the plank to lie flat, this must be countered with an opposing
thermal treatment on the back side of the HPL/PVC Plank Assembly.
Thermal treatment can be done in line by directly heating (in an
upward direction) the bottom surface of the plank while the plank
is undergoing the wrapping process.
For the specific HPL/PVC Plank geometry shown in FIG. 1, it has
been found that by heating the back surface of the assembly to
certain temperatures for certain times, the shape of the board can
be controlled. In fact, the cupping can be corrected and a flat
plank produced if the board is heated to 240 300 degrees F. for 20
45 seconds.
If the board is allowed to reside at higher temperatures for longer
times, a "doming" can actually be induced into the board. So total
control of the ultimate shape of the board can be achieved by
appropriate selection of conditions.
The thermoplastic plank of the present invention was tested for
properties and compared to commercially available Mannington
laminate and wood flooring products.
The can drop test involved dropping a 2 lb can from 40 inches high,
wherein 100% means a puncture of the product and 0% means no chip
off.
Extrusion Plank Testing
TABLE-US-00005 Mannington Product Extrusion Plank Test Designation
Laminate Wood Plank Only With Overlay Taber Abrasion, cycles to IP
9880 125 5 mils @ 500 5590 Can Drop, mils indent* MD, no feet 30,
100% cat 50, 100% cat 5, 16% cat 5, 0% cat AMD, no feet 30, 100%
cat 31, 100% cat 1, 0% cat 1, 0% cat MD, with feet -- -- 7, 28% cat
5, 60% cat AMD, with feet 1, 0% cat 0, 0% cat Pneumatic Indent,
mils indent No feet 0 3.6 0.2 0 With feet -- -- 0.2 0.2 Two hour
stain KC-261 Asphalt (Sealer) 0.5 0 3 0 Shoe Polish 0 1 0 0 Oil
Brown 0.5 0 0 0 Mustard 0 0 0 0 Chemlawn 0 0 0 0 Blue Sharpie 0.5
0.5 0.5 0 Iodine 0 3 0 0 Total Stain 1.5 4.5 3.5 0 Static Load,
mils indent No feet 0 1 0 0 With feet -- -- 0 0 Sliding Gouge MD,
no feet 250 psi pass pass pass pass 300 psi pass fail pass pass 350
psi pass fail pass pass AMD, no feet 250 psi pass pass pass pass
300 psi pass fail pass pass 350 psi pass fail pass pass MD, with
feet 250 psi -- -- pass pass 300 psi -- -- pass pass 350 psi -- --
pass pass AMD, with feet 250 psi -- -- pass pass 300 psi -- -- pass
pass 350 psi -- -- pass pass Two hour boiling water fail fail pass
pass Large ball impact, inches to failure No Feet 14 10 32, no
failure 32, no failure With Feet 32, with pad -- 32, no failure 32,
no failure This row indicated "cat" as catastrophic failure meaning
puncture through.
Example 2
A series of thermoplastic planks similar in design to the planks
formed in Example 1 were connected together to create a flooring
system. The spline system as set forth in FIG. 3 was used. In
addition, a comparison was made with using no bonding agent and a
flooring system using a bonding agent. The bonding agent,
tetrahydrofuran (THF) was applied to all sides of the plank
including the spline and grooves. When no THF was applied to the
spline area, the bonding strength was an average of 1.73 pounds
using the Instron test with the following parameters: 50 pounds
full scale for the chart paper, 0.5 in/minute jaw speed, 3 inch jaw
distance, 1.times.5 sample, 156 mil spline thickness. When the same
type of extrusion plank had THF applied to the spline area, after 4
hours curing, the bonding strength of the spline area was an
average of 18.1 pounds and after 24 hours curing, the bonding
strength of the spline area was 39.1 pounds. The ends of the
extrusion plank were tested for bonding strength wherein the ends
have no spline attachment and simply butted against each other.
There was no bonding strength when no THF was present since there
is nothing holding the edges of each plank together. When THF was
applied to the edges after 4 hours cure, the bonding strength was
over 100 pounds using a 100 pound scale, and after a 24 hour cure,
the bonding strength was over 100 pounds using a 100 pound scale.
When the test was repeated with a 152 mil spline with THF, using
the INSTRON test, after 24 hour cure, the bonding strength was an
average of 45.37 pounds.
A rolling secretary test using 165 pounds was then used. In this
test, a 20 by 30 inch panel was used wherein a half of the panel
was THF bonded over 24 hours and the other half of the panel had
only splines holding the panels together. This panel was then laid
on a carpet which caused movement up and down on the panel. The
product with the 156 mils spline separated after 20 cycles and the
other half of the product, which was sealed with THF, did not
separate after 150 cycles. This was impressive considering the
panel was not glued down to any surface.
A second panel was then made and placed on a sterling board with
felt shim (0.26 inch) and placed in different places on the PVC
board. This was done to cause unevenness in the subfloor. Upon
doing the rolling secretary test again, the planks did not separate
with the THF present.
Both products were then tested by placing them on towels and water
was placed on the end cuts and the spline area. After 10 minutes,
the water was wiped and the THF end cut area had very little
penetration of water wherein the non-sealed area did show signs of
leakage.
In the 75 pound slider test which was developed as a spline
strength test, a 12 inch long spline was inserted into the tongue
of a 12 inch plank and then a second plank was connected to the
other side of the spline in order to connect two planks together. A
hole was then drilled in the middle of one of the planks. With the
two planks connected together, 75 pounds was placed on the plank
without the hole and a 50 pound fish scale was hooked to the plank
with the drilled hole and slowly pulled until the connected planks
separated. With a 150 mil thick spline and a vertical gap thickness
of PVC plank of approximately 154 mil on average, the product
pulled apart from the spline after a static friction reading of
about 25 pounds initial pull wherein the pull was done on a Lauan
substrate. Using a spline that was 156 mil thick, the spline went
in with some tapping and the test was done both on a Lauan and
Sterling board substrate which gave different readings on the fish
scale. With respect to the Sterling board substrate (static
friction) of 40 pounds and (dynamic friction) of 35 pounds, the
product did not pull apart. With respect to the Lauan (static
friction) of 25 pounds and (dynamic friction) of 20 pounds, the
product did not pull apart. A 159 mil spline was then used which
was hard to install due to the thickness of the receiving tongue,
in this test, Sterling (static friction) of 35 pounds and (dynamic
friction) pulled apart but took some effort and the products did
not move at all. With respect to the Lauan (static friction) of 35
pounds and (dynamic friction) of 30 pounds, the product slid but no
separation.
In view of the above testing, these examples show that the addition
of THF as a bonding agent provides significant strength advantages
to the overall surface covering systems and also prevents water
penetration to the subfloor especially at the edges where there is
no spline system used.
Other embodiments of the present invention will be apparent to
those skilled in the art from consideration of the specification
and practice of the present invention disclosed herein. It is
intended that the specification and examples be considered as
exemplary only, with the true scope and spirit of the present
invention being indicated by the following claims.
* * * * *